U.S. patent application number 11/970633 was filed with the patent office on 2012-06-07 for plasticized polyvinyl chloride composition with flame retardant.
This patent application is currently assigned to UNITEX CHEMICAL CORPORATION. Invention is credited to James F. Day.
Application Number | 20120142839 11/970633 |
Document ID | / |
Family ID | 46162819 |
Filed Date | 2012-06-07 |
United States Patent
Application |
20120142839 |
Kind Code |
A1 |
Day; James F. |
June 7, 2012 |
Plasticized polyvinyl chloride composition with flame retardant
Abstract
A highly flame retardant plasticized polyvinyl chloride
composition includes a mixture of a dialkyl or dialkenyl
tetrahalophthalate and a brominated/chlorinated paraffin. The
composition exhibits an absence of brittleness, and substantial
flexibility at low temperatures. The composition can be used to
form sheet materials, molding compositions, roofing materials, PVC
formed jackets and insulation for wire and cable products.
Inventors: |
Day; James F.;
(Winston-Salem, NC) |
Assignee: |
UNITEX CHEMICAL CORPORATION
Greensboro
NC
|
Family ID: |
46162819 |
Appl. No.: |
11/970633 |
Filed: |
January 8, 2008 |
Current U.S.
Class: |
524/288 |
Current CPC
Class: |
C08K 5/12 20130101; C08L
27/06 20130101; C08L 27/06 20130101; C08K 5/02 20130101; C08K 5/02
20130101; C08K 5/1539 20130101; C08K 5/12 20130101 |
Class at
Publication: |
524/288 |
International
Class: |
C08L 27/06 20060101
C08L027/06; C08K 5/02 20060101 C08K005/02; C09D 127/06 20060101
C09D127/06; C08K 3/22 20060101 C08K003/22; C08K 3/10 20060101
C08K003/10; C08K 5/095 20060101 C08K005/095; C08K 5/092 20060101
C08K005/092 |
Claims
1. A flexible PVC composition comprising: a polyvinyl chloride
resin; at least one dialkyl or dialkenyl tetrahalophthalate
plasticizer in an amount sufficient to increase flexibility of said
composition; and at least one halogenated paraffin flame retardant
in an amount to enhance flexibility at low temperatures and reduce
brittleness of the composition.
2. The flexible PVC composition of claim 1, wherein said at least
one dialkyl tetrahalophthalate comprises a mixture of dialkyl of
tetrabromophthalate and dialkyl tetrachlorophthalate.
3. The flexible PVC composition of claim 1, wherein said
composition comprises a mixture of a dialkyl tetrachlorophthalate
and a dialkyl tetrabromophthalate in a ratio of about 1:4 to about
1:3 by weight.
4. The flexible PVC composition of claim 1, wherein said
halogenated paraffin is included in an amount of at least 5 parts
by weight per 100 parts by weight of the polyvinyl chloride
resin.
5. The flexible PVC composition of claim 1, wherein said
halogenated paraffin is included in an amount of at least 10 parts
by weight based on 100 parts by weight of the polyvinyl chloride
resin, and where the dialkyl tetrahalophthalate is included in an
amount sufficient to inhibit separation of the halogenated paraffin
from the polyvinyl chloride composition.
6. The flexible PVC composition of claim 1, wherein said
halogenated paraffin is present in an amount within a range of
about 25-33% by weight based on the combined weight of the
halogenated paraffin and the dialkyl tetrahalophthalate.
7. The flexible PVC composition of claim 1, wherein said dialkyl
tetrahalophthalate is included in an amount of about 1 wt % to
about 99 wt % based on the combined weight of the dialkyl
tetrahalophthalate and halogenated paraffin.
8. The flexible PVC composition of claim 1, wherein said dialkyl
tetrahalophthalate is included in an amount of about 1 wt % to
about 50 wt % based on the combined weight of the dialkyl
tetrahalophthalate and the halogenated paraffin.
9. The flexible PVC composition of claim 1, wherein said dialkyl
tetrahalophthalate is included in an amount of about 25 wt % to
about 33 wt % based on the combined weight of the dialkyl
tetrahalophthalate and the halogenated paraffin.
10. The flexible PVC composition of claim 1, wherein said dialkyl
tetrahalophthalate is included in an amount of about 5-20 wt % and
the halogenated paraffin in an amount of about 3-10 wt % based on
the total weight of the polyvinyl chloride composition.
11. The flexible PVC composition of claim 1, further comprising a
second plasticizer, a flame retardant synergist and a
stabilizer.
12. The flexible PVC composition of claim 1, further comprising a
triocty trimellitate plasticizer, antimony oxide, and a calcium
zinc stabilizer.
13. The flexible PVC composition of claim 1, wherein the dialkyl
tetrahalophthalate is selected from the group consisting of
bis-2-ethylhexyl tetrachlorophthalate, bis-2-ethylhexyl
tetrabromophthalate, bis-trimethylhexyl tetrabromophthalate,
bis-isodecyl tetrabromophthalate, bis-isotridecyl
tetrabromophthalate and bis-octyl tetrabromophthalate.
14. The flexible PVC composition of claim 1, wherein the dialkyl or
dialkenyl tetrahalophthalate is a C.sub.5 to C.sub.15 alkyl or
alkenyl tetrahalophthalate.
15. The flexible PVC composition of claim 1, wherein the
halogenated paraffin is a liquid halogenated C.sub.10-C.sub.30
alkyl having a halogen content of about 30 wt % to about 70 wt %
based on the total weight of the paraffin.
16. A PVC composition comprising: polyvinyl resin; a flame
retardant synergist; a stabilizer; and a mixture of a dialkyl or
dialkylene tetrahalophthalate and a halogenated paraffin in an
amount effective to provide a predetermined flexibility fire
retardant and smoke suppressant properties.
17. The flexible PVC composition of claim 16, wherein said mixture
comprises about 1 wt % to about 50 wt % of said dialkyl or
dialkenyl tetrahalophthalate based on the total weight of the
dialkyl or dialkenyl tetrahalophthalate and halogenated
paraffin.
18. The flexible PVC composition of claim 16, wherein said mixture
comprises about 25 wt % to about 33 wt % of said dialkyl or
dialkenyl tetrahalophthalate based on the total weight of said
dialkyl or dialkenyl tetrahalophthalate and halogenated
paraffin.
19. The flexible PVC composition of claim 16, wherein said
composition comprises about 5-20 wt % of said dialkyl or dialkenyl
tetrabromophthalate and about 3-10 wt % of said halogenated
paraffin based on the total weight of the PVC composition.
20. The flexible PVC composition of claim 16, wherein said
composition is a coating composition or molding composition.
21. The flexible PVC composition of claim 16, wherein said
composition is in the form of a sheet.
Description
FIELD OF THE INVENTION
[0001] This invention relates to a highly flame retardant,
plasticized polyvinyl chloride (PVC) composition characterized by
an absence of brittleness at low temperatures, substantial
flexibility and low smoke properties. PVC formulations of the
invention can be used for molding compositions, sheet materials,
coating materials and electrical insulation materials. The
composition of the invention is also suitable for PVC formed
jackets, insulation for wire and cable products and roof
sheathing.
BACKGROUND OF THE INVENTION
[0002] PVC compounds are a well known class of thermoplastic
polymers which exhibit excellent chemical and corrosion resistance,
physical and mechanical strength, and electrical insulative
properties. Unplasticized versions of PVC are inherently flame
resistant, and rigid PVC compounds require only additional antimony
trioxide to achieve a high level of flame retardancy. When flexible
forms of PVC are required, however, the addition of plasticizers to
the formulation can increase its flammability. Conventional PVC is
also apt to produce excessive smoke when exposed to ignition
temperatures.
[0003] As is well known in the art, flame retardants must be in
liquid form to plasticize PVC. See, Handbook of Polyvinyl Chloride
Formulating, edited by Edward J. Wickson, 818-831, John Wiley &
Sons (1993). The disclosure of this publication and all other
publications and patents referred to herein are incorporated herein
by reference.
[0004] Both triaryl and diaryl alkyl phosphate esters have been
used to improve the flame retardancy of PVC. Nonetheless,
continuing increases in demands in even better flame retardant
properties for evermore stringent flexible PVC applications
continue to challenge manufacturers.
[0005] The addition of dialkyl tetrahalophthalates such as dioctyl
tetrabromophthalate or di-2-ethylhexyltetrabromophthalate has been
able to achieve exceptional thermal stability and flame retardancy.
The low temperature flexibility of PVC compounds is, however,
compromised with the addition of such compounds.
[0006] There remains a continuing need in the art for even greater
flexibility for PVC formulations and coatings.
[0007] When PVC burns, it gives off soot and suspended particles
which are generally termed "smoke." Although there is increasing
demands for flexibility with thermal stability and flame
retardancy, smoke generation is still an issue. As mentioned
previously, the use of plasticizers necessary for flexibility and
good processing properties generally increases the flammability of
PVC compositions, especially if used at high levels. Although flame
retardants are added to counteract the flammability of the
plasticizers and reduce flammability of PVC compositions, they
unfortunately increase smoke generation over the already
considerable amount of smoke produced when PVC burns. In the case
of plasticized PVC, the compounds forming the smoke can include not
only the hydrocarbons, carbon oxides, and HCl from the PVC, but
also the plasticizer compounds as well as their degradation
products. The degradation products can also include aromatic and
aliphatic hydrocarbons, carbon oxides, and hydrochloric acid. Smoke
is particularly dangerous since it not only contains toxic
by-products of combustion and thermal decomposition of the plastic.
Smoke also restricts visibility and disorients potential victims,
resulting in panic. Therefore, smoke suppressants, compounds which
will inhibit the formation of smoke when the PVC composition burns,
were developed.
[0008] The plastics industry has long recognized that the use of
PVC in interior furnishings, building materials, and coverings for
wire and cable presents the hazards of flame, toxic decomposition
products, and smoke in the event of fire. It has therefore expended
very considerable efforts to find additives for PVC which reduce
smoke in the event that such PVC compositions are subjected to high
temperatures or flame.
[0009] The most commercially recognized material for smoke
suppression in PVC is ammonium octamolybdate (AOM). AOM is the
premium material to make low smoke PVC compounds, particularly for
plenum wire and cable applications. AOM is used in numerous PVC
jacket formulations that pass the rigorous UL910 test for cables
(copper conductor and fiber optic cables).
[0010] U.S. Pat. No. 4,153,792 discloses the production of amine
molybdates as smoke suppressants, especially melamine molybdate by
reacting an amine, such as melamine, with molybdenum trioxide in an
aqueous acidic medium under reflux.
[0011] U.S. Pat. No. 4,217,292 also discloses the production of
amine molybdates as smoke suppressants, preferably melamine
molybdate by reacting an amine such as melamine with a
stoichiometric quantity of molybdenum trioxide in an aqueous medium
in the presence of an ammonium salt. The aqueous medium is
essentially free of acid. The reaction may be conducted at
temperatures within the range of 75-110.degree. C.
[0012] Organic salts of divalent copper are also well known as
smoke suppressants for polyvinyl chloride resins. Most studies were
done using copper (II) acetate or copper (II) formate. These
materials were designed to undergo decomposition to ground state
copper (Cu.degree.). This is referred to as a reductive coupling
mechanism. Reductive coupling results in significant reduction of
smoke upon ignition due to char formation. Copper in its ground
state is active in reductive coupling of halogenated resins. The
difficulty with copper (II) salts is two fold. The first difficulty
is that the salts are blue or blue-green in color which also colors
the resin systems. Secondly, the salts upon decomposition cause
instability of the halogenated resin by dechlorination without
reductive coupling. This dechlorination accelerates decomposition
to olefinic species.
[0013] The use of melamine molybdate and copper compounds such as
copper acetate, copper oxalate, and copper formate as smoke
suppressants in halogenated resins, particularly PVC, is well
known. This technology was never commercialized due to the
technical failures of these systems. The pitfalls included blue to
green discoloration of the resin systems, and poor thermal
stability of the compounded resin systems, and loss of fire
resistance characteristics due to the thermal instability of the
compounded resin systems.
[0014] A variety of organic and inorganic compounds and salts have
been proposed or used to reduce the smoke generation
characteristics of rigid or plasticized PVC polymer compositions,
but such agents have drawbacks such as not providing an improvement
in smoke suppression for both rigid and plasticized PVC
compositions, and unduly reducing the stability or processability
of the polymer composition.
[0015] Another drawback with some agents employed to impart smoke
suppression to PVC compositions unduly decrease the heat stability
of the polymer compositions in which they are incorporated. In
particular, some commercial smoke suppressant additives based on
zinc compounds or combinations of zinc compounds with other
compounds contain free zinc oxide, which can accelerate the
degradation of PVC resins on exposure to temperatures above about
100.degree. C.
[0016] In the area of PVC-based compositions for wire and cable
covering applications, it is very desirable to have materials
produce a minimum amount of smoke when burned, and produce
light-colored smoke rather than dark smoke, while still possessing
the good processing properties, mechanical toughness, and
resistance to environmental stresses for which PVC compositions are
known.
[0017] Accordingly, there is a continuing need for a PVC
formulation having both high flexibility and very low smoke.
SUMMARY OF THE INVENTION
[0018] A feature of this invention is to provide low temperature
flexibility of highly flame retardant plasticized PVC compounds by
incorporating into PVC, according to the discovery of the
invention, a mixture of a dialkyl or dialkylene tetrahalophthalate
containing both tetrabromophthalates and tetrachlorophthalates and
a brominated and/or chlorinated paraffin.
[0019] A further feature of this invention is to provide a PVC
formulation that exhibits a decrease in smoke generation.
[0020] Another feature of the invention is to provide an improved
PVC formulation for use in products such as molding compositions to
form molded articles, sheet materials, roofing materials,
insulation, jackets, coatings and articles of clothing.
[0021] A further feature of the invention is to provide a polyvinyl
chloride composition containing a dialkyl tetrahalophthalate and a
halogenated paraffin where the dialkyl tetrahalophthalate is
included in an amount sufficient to inhibit separation of the
liquid halogenated paraffin from the polyvinyl chloride composition
and provide the desired flexible characteristics. The dialkyl
tetrahalophthalate when used in combination with the halogenated
paraffin enables the halogenated paraffin to be used in amounts
greater than when the halogenated paraffin is used alone.
[0022] In the present invention, it has been discovered that the
addition of a halogenated paraffin to a PVC flexibilizing
formulation comprising one or more tetrahalophthalates further
lowers smoke generation, improves flame retardancy and improves low
temperature brittleness without adversely affecting PVC
flexibility. Such formulations are useful as outer jackets and
insulators for plenum wires and cables, wire coverings, articles of
clothing including weatherproof apparel, flexible layers under roof
sheathing, other roll and sheet based layers used in residential
and commercial construction, shingles or other roof coverings, and
flexible coatings applied to fabrics.
[0023] The various aspects of the invention are basically attained
by providing a flexible PVC composition comprising a polyvinyl
chloride resin, at least one tetrahalophthalate plasticizer in an
amount sufficient to promote flexibility of the PVC composition,
and a halogenated paraffin in an amount to provide flame and smoke
retardant properties.
[0024] These and other aspects of the invention will become
apparent from the following detailed description of the invention
which discloses various embodiments of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0025] The present invention is directed to a polyvinyl chloride
composition having flame retardant and smoke suppressing
properties. The polyvinyl chloride compositions are suitable as
molding compositions for forming molded articles, sheet goods such
as roofing materials, coatings, coverings and insulation for wires
and cables. The invention is further directed to a flame retardant
and smoke suppressant agent that can be used in conjunction with a
plasticizer for polyvinyl chloride resins. PVC containing at least
one tetrahalophthalate, especially a mixture of tetrabromophthalate
and tetrachlorophthalate, with a halogenated (especially brominated
and/or chlorinated) paraffin show significant improvements in low
temperature flexibility and decreased smoke generation potential.
PVC compounds of the present invention also result in synergist
improvements of flame retardancy with decreased smoke generation.
The tetrahalophthalate is preferably a dialkyl or dialkenyl
tetrahalophthalate.
[0026] PVC formulations according to one embodiment of the
invention comprise: (A) a flexibilizing agent that includes one or
more dialkyl or dialkenyl tetrahalophthalates, and (B) a smoke
inhibitor that includes one or more halogenated alkyl hydrocarbons
that are a liquid or solid form at 25.degree. C. The halogenated
alkyl hydrocarbons are preferably liquid halogenated paraffins. It
has been found that the combination of the tetrahalophthalates and
the halogenated paraffin provide improved flame and smoke
retardancy than when the components are used individually in
corresponding amounts without reducing the flexibility of the PVC
composition.
[0027] The polyvinyl chloride composition of the invention
preferably contains a mixture of at least one dialkyl or dialkenyl
tetrahalophthalate and at least one halogenated paraffin where the
various components do not separate from the PVC composition. The
polyvinyl chloride composition in one embodiment includes at least
5 parts by weight and typically at least 10 parts by weight of the
halogenated paraffin based on 100 parts by weight of the polyvinyl
chloride resin. The dialkyl or dialkenyl tetrahalophthalate is
included in an amount to provide the desired flexibility and to
prevent the halogenated paraffin from separating or exuding from
the polyvinyl chloride composition. It has been found that the
halogenated paraffin can be added without reducing the
flexibilizing properties of the tetrahalophthalate.
[0028] The dialkyl or dialkenyl tetrahalophthalate flexibilizing
agents that can be used in the invention include one or more of
fluoro-, chloro-, bromo-, and/or iodo-substituted dialkyl or
dialkenyl tetrahalophthalates. Improved low temperature flexibility
for PVC can be achieved with dialkyl tetrahalophthalate mixtures
that are not adversely effected by the presence of the halogenated
paraffin. Dialkyl tetrahalophthalates are disclosed in U.S. Pat.
Nos. 6,534,575; 6,114,425 and 5,728,323, the disclosures of which
are hereby incorporated by reference. Dialkyl or dialkenyl
tetrahalophthalates useful in the present invention exhibit the
following chemical structure:
##STR00001##
wherein:
[0029] R is an alkyl or alkenyl having 5-15 carbon atoms,
[0030] R' is alkyl or alkenyl having 5-15 carbon atoms, and where R
and R' can be the same or different, and
[0031] X is independently F, Cl, Br or I.
[0032] In one preferred embodiment, R and R' are independently a
C.sub.9-C.sub.11 alkyl or alkenyl.
[0033] The dialkyl or dialkenyl tetrahalophthalates used in the PVC
compound of the present invention may be prepared using methods
known in the art. Preferably, the dialkyl tetrahalophthalates used
in the PVC compound of the present invention are prepared in
accordance with the teachings in U.S. Pat. No. 6,114,425 to Day et
al, the disclosure of which is hereby incorporated by
reference.
[0034] The tetrahalophthalate compounds provide improved low
temperature flexibility, increased flame retardancy and decreased
smoke generation of polyvinyl chloride resins.
[0035] Dialkyl tetrahalophthalate compounds useful in the present
invention are preferably included at a concentration within the
range of about 0.01-25% by weight based on total weight of the PVC
composition depending on the degree of flexibility desired for the
final product and the PVC material.
[0036] In one embodiment of the invention, two or more dialkyl
tetrahalophthalates are used in combination. The weight ratio of
the two dialkyl tetrahalophthalate flexibilizing agents in the
mixture can be within the range from about 1:50 to about 1:1. In
another embodiment a dialkyl tetrachlorophthalate can be used in
combination with a dialkyl tetrabromophthalate preferably within
the range of 1:10 to about 1:8, and most preferably about 1:4 to
about 1:3 dialkyl. In one embodiment of the invention, the dialkyl
tetrahalophthalate includes a mixture of dialkyl
tetrachlorophthalate and dialkyl tetrabromophthalate where the
mixture includes the dialkyl tetrachlorophthalate in an amount of
about 1 to 99 wt %, preferably about 1 to 50 wt %, and more
preferably about 25 to 33 wt % based on the total weight of the
mixture.
[0037] The halogenated alkyl hydrocarbon smoke suppressing agents
used according to the invention preferably include brominated
and/or chlorinated alkyl compounds, preferably in the form of
halogenated paraffinic materials. The smoke suppressing agents are
preferably paraffinic hydrocarbons having a halogen content of
about 30 wt % to about 70 wt % based on the weight of the paraffin.
In one embodiment, the paraffin is liquid at room temperature and
about 10-30 carbon atoms.
[0038] The halogenated paraffin can be a brominated paraffin, a
chlorinated paraffin, a bromochlorinated paraffin, and mixtures
thereof produced from a straight chain C.sub.10 to C.sub.20 alkyl.
In one embodiment, the smoke suppressing agent is a
bromochlorinated liquid paraffin having substantially equal amounts
of bromine and chlorine by weight based on the weight of the liquid
paraffin. In an embodiment of the invention, the liquid paraffin
can have a bromine content of about 15 wt % to about 35 wt % and a
chlorine content of about 15 wt % to about 35 wt % based on the
total weight of the paraffin. In another embodiment, the liquid
paraffin can have a bromine content of about 30 wt % to about 35 wt
% and a chlorine content of 30 wt % to 3 wt % based on the total
weight of the liquid paraffin.
[0039] Examples of suitable halogenated paraffins useful in the
invention include commercially available liquid halogenated
materials sold under the trade name DOVERGUARD (Dover Chemical
Corporation, Dover, Ohio). DOVERGUARD 9119 (Dover Chemical
Corporation, Dover, Ohio) is an example of one preferred material
having 33 wt % bromine and 33 wt % chlorine in an unspecified
variety of olefins that exhibits a Gardner color of 1, a viscosity
of 65 poise at 25.degree. C., and a specific gravity of 1.58 at
50.degree. C. Commercially available halogenated paraffins are a
mixture or blend of halogenated straight chain C.sub.10-C.sub.30
alkyls.
[0040] The halogenated paraffin can be used in an amount within the
range of about 1-99% by weight based on the combined weight of the
dialkyl tetrahalophthalate and halogenated paraffin mixture. In
another embodiment, the halogenated paraffin is included in an
amount of about 1 to 50 wt %, and more preferably 25 to 33 wt %
based on the combined weight of the dialkyl tetrahalophthalate and
halogenated paraffin mixture.
[0041] Mixtures of dialkyl tetrahalophthalate and halogenated
paraffin can be prepared in any of a number of ways. For example,
the dialkyl tetrahalophthalate flexibilizing agents can be mixed
until homogeneous. The tetrahalophthalates can then be combined
with the halogenated paraffin and added as a mixture to the PVC
resin or the components can be added separately.
[0042] In one embodiment, the PVC formulation also includes a flame
retardant synergist (e.g., antimony trioxide), a further
plasticizer (e.g., trioctyl trimellitate), and/or a stabilizer
(e.g., a calcium-zinc stabilizer).
[0043] The mixture or combination of the dialkyl tetrahalophthalate
and halogenated paraffin are admixed with the polyvinyl chloride
resin in an amount to provide the desired flexibility, flame and
smoke retardancy. For example, the mixture or combined weight of
the dialkyl tetrahalophthalate and halogenated paraffin can range
from about 10 wt % to 25 wt %, and preferably about 15 wt % to 20
wt % based on the total weight of the polyvinyl chloride
composition. In another embodiment, the combined weight of the
dialkyl tetrahalophthalate and halogenated paraffin is about 20
parts by weight to about 40 parts by weight, and preferably about
25 parts by weight to 35 parts by weight based on 100 parts by
weight of the polyvinyl chloride resin. The dialkyl or dialkenyl
tetrahalophthalate is typically included in an amount of about
15-25 parts by weight, and preferably about 18-22 parts by weight
based on 100 parts by weight of the polyvinylchloride. The
halogenated paraffin is typically included in an amount of about
5-15 parts by weight, and preferably about 8-12 parts by weight
based on 100 parts by weight of the polyvinyl chloride resin.
[0044] The finished polyvinyl chloride composition typically
contains about 10 wt % to about 12 wt % dialkyl tetrahalophthalate
and about 5 wt % to about 7 wt % halogenated paraffin based on the
total weight of the polyvinyl chloride resin composition. In other
embodiments, the polyvinyl chloride composition can include the
dialkyl tetrahalophthalate in an amount of about 5-20 wt % and the
halogenated paraffin in an amount of about 3-10 wt % based on the
total weight of the polyvinyl chloride composition.
[0045] It has been found that the combination of the dialkyl
tetrahalophthalate and the halogenated paraffin provide improved
flexibility and flame and smoke retardancy that cannot be obtained
by the component individually. In particular, it has been found
that the halogenated paraffin by itself has limited dispersibility
in the polyvinyl chloride resin. Amounts of the halogenated
paraffin without the use of the dialkyl tetrahalophthalate in
amounts greater than 5 parts by weight per 100 parts by weight of
the polyvinyl chloride resin separate and exuded from the resin
composition as a sticky oil. When used in combination with the
dialkyl tetrahalophthalate, the amount of the halogenated paraffin
can be incorporated in amounts of at least 10 parts and up to 15
parts by weight based on 100 parts by weight of the polyvinyl
chloride resin.
EXAMPLES
[0046] For Examples 1-3, the base PVC polymer, plasticizer,
stabilizer, flame retardant synergist, and the dialkyl
tetrahalophthalate-brominated/chlorinated paraffin mixture were
combined and thoroughly mixed. Initial mixing of the ingredients
was carried out in a blender. The resulting charge was transferred
to a 2 roll mill and preheated to 350.degree. F. for fusion and
further mixing. Rolling time was for 5 minutes under 1260 psi
compression at 337.degree. F. for compression molding of the
mixture into test sheets.
[0047] The standard for PVC compression molding as known in the art
is described in standardized test methods ASTM Designation:
D-1928-90 and ASTM D-746, which are herein incorporated reference.
Standardized test methods ASTM D-1928-90 and ASTM D-746 disclose
the protocol for preparing compression molded polyethylene test
sheets and PVC compression molding of the mixture into test
specimens. In the present case, the specimens prepared according to
these standards were subjected to physical, mechanical, and flame
retardancy testing as described below.
[0048] Each example included tests to determine the tensile
properties of the compressed PVC using standard dumbbell-shaped
test specimens according to ASTM Designation D-638, published in
1995. In this test method, the test specimen is clamped by and
between grips. The grips extend in opposed directions thereby
stretching the test specimens until the specimen breaks. The test
measures: (1) Tensile Modulus, which is the ratio of stress to
corresponding strain below the proportional limit of a material and
expressed in force per unit area (2) Tensile Strength at Break,
which is the maximum tensile stress (tensile load per unit area of
minimum original cross section) sustained by the specimen during a
tension test at specimen break, and (3) Elongation, which is the
elongation of a test specimen expressed as a percent of the gage
length. An increase in these test factors indicates a more flexible
test specimen.
[0049] Test specimen hardness was also measured. The standard
hardness test method is found in the ASTM D-2240, published in
1995. This test results are based on the penetration of an indentor
when forced into the test specimen.
[0050] Flame retardancy of the control and test formulations were
determined by the Designation ASTM D-2863, published in 1995, to
give oxygen index values. The oxygen index is equal to the minimum
concentration of oxygen, expressed as volume percent, in a mixture
of oxygen and nitrogen that will just support flaming combustion of
a material initially at room temperature. A higher oxygen index
indicates higher flame retardancy.
[0051] The test specimens were tested for the density of smoke
generated by burning the test specimens in an NBS Smoke Chamber
using the flaming mode in accordance with the ASTM E662-95
publication.
[0052] The test specimens were also tested for Brittleness
Temperature. The brittleness of a test specimen is determined by
immersing the specimen in a bath containing a heat transfer medium
that is cooled. The specimens are struck at a striking element at a
specified linear speed and then examined. The brittleness
temperature is the temperature at which 50% of the specimens
fail.
[0053] PVC resin (the base PVC resin used was GEON 30 from the Geon
Corporation, now PolyOne Corporation) was compounded in a 2 roll
mill in accordance with the procedures disclosed in ASTM D-1928
using the below mentioned Control and Test Formulations.
Examples 1-3
[0054] Examples 1-3 were prepared and tested according to the
procedures discussed above. The proportions, components and test
results are presented in Table 1.
TABLE-US-00001 TABLE 1 Example 1 (CONTROL) Example 2 Example 3 PVC
Resin (Geon 30) 100 100 100 Trioctyl Trimellitate 34.3 34.3 34.3
(UNIPLEX 546-A) Bis (2-Ethylhexyl -- 20 -- tetrachlorophthalate
Brominated/Chlorinated -- 10 10 Paraffin (DOVERGUARD 9119)
Bis(2-Ethylhexyl 30 -- 20 tetrabromophthalate) (UNIPLEX FRP-45)
Antimony Oxide 5 5 5 Calcium-Zinc Stabilizer 5 5 5 Tensile Modulus
at 100% 1760 2070 1900 Shore A Hardness (ASTM 88 88 90 D-224095, A
Scale) Tensile Strength at Break 2050 3480 3330 (ASTM D638-95)
Elongation (%)(ASTM 278 390 360 D638-95) Oxygen Index (ASTM 33 37
41 D2863-95) NBS Smoke(ASTM E662- 440 240 265 95) Brittleness
Temperature, -12 -40 -32 .degree. C. (ASTM D746-95)
[0055] The data in Table 1 shows that Examples 2 and 3 exhibited
improved tensile modulus, tensile strength, elongation, oxygen
index, smoke and brittleness relative to the control of Example 1.
Both Examples 2 and 3, respectively, exhibited an 18% and 8%
improvement in tensile modulus, 70% and 62% increase in tensile
strength at break, 40% and 29% increase in tensile strength
elongation, 12% and 24% increase in oxygen index, 45% and 40%
decrease in NBS smoke and 233% and 167% increase in brittleness
temperature.
[0056] The test data of Table 1 shows that the polyvinyl chloride
resin composition that contain the halogenated paraffin exhibited
an increase in tensile modulus, tensile strength, elongation,
oxygen index, smoke and brittleness compared to Example 1 which
contained only Bis-2-ethylhexyl-tetrabromophthalate. The
differences between Examples 2 and 3 are due to the specific
dialkyl tetrahalophthalate. Examples 2 and 3 which contained 10
parts by weight of the brominated/chlorinated paraffin exhibited no
separation of the compound from the compositions. Previous samples
prepared without the dialkyl tetrahalophthalate exhibit separation
of the brominated/chlorinated paraffin when present in amounts
greater than 5 parts by weight based on 100 parts by weight of the
PVC resin.
[0057] While advantageous embodiments have been chosen to
illustrate the invention, it will be understood by those skilled in
the art that various changes and modifications can be made therein
without departing from the scope of the invention as defined in the
appended claims.
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